Does Human Fertility Adjust to the Environment?

Abstract

Both theory and empirical research on historical American fertility suggest that human fertility responds of voluntarily to environmental co nditions. In the economic theory of fertility tastes prices and inco me determine the optimal number of children. These influences lead to the expectation of the following ordering of areas from high to low fertility at any given time: frontier settled agricultural new urban areas and old urban areas. Over time it can be expected that fertility would decline as new areas age e.g. frontier areas become settled agriculture and new urban areas become old urban areas. These expectations are supported by the available evidence. In the early 1800s fertility was lower in the older settled areas of the East than in those undergoing settlement; and within every division urban fertility is lower than rural fertility. The American fertility decline reflects not only the processes of urbanization and industrialization but that of settlement as well. The problem is whether the voluntary response of fertility to environmental pressures results in a socially optimal adjustment.